1. Field of the Invention
The present invention relates to recording and reproducing apparatuses, and more particularly to recording apparatuses capable of recording digital data using a single-file format and to reproducing apparatuses for reproducing a file recorded in a single-file format.
2. Background of the Invention
In recent years, digital recording apparatuses such as digital cameras and camcorders have rapidly become more popular. This popularity is due in part because there is no film involved. Images are saved in memory for downloading to a personal computer (PC) and instead of loading film, rewinding it, having it processed and paying for prints, an operator can edit and crop the digital images using PC software and print the results on a color printer. Such editing and enhancing operations can be performed directly on the recording apparatus or on the PC. Furthermore, digital images can be composed after the fact by reframing them.
At the heart of any digital recording apparatus is a microprocessor, FPGA, ASIC, or other processing device for executing computer software to perform various camera operation features. In recent years, these processing devices have become not only smaller and more efficient, but more powerful as well. Manufacturers are using this power to make digital recording apparatuses easier to use and to incorporate in them a variety of advanced features.
For example, many of today's digital recording apparatuses can operate in several recording modes, such as a still mode for recording individual photographic frames, a continuous mode for recording a series of photographic frames, and a movie mode for recording photographic frames at video frame rates, as well as sound. Some of today's recording apparatus also have an audio recording feature for including recorded audio with movie image files or recording separate audio files. Similarly, text can be input by the operator, which can also be overlaid onto a reproduced image or saved as individual text files. In each of the above-mentioned modes, the recording apparatus creates files which are organized in one or more directories in a memory.
Recorded files, such as digital still image files, digital movie files, digital audio files, and text files are processed and reproduced by a host of different reproducing apparatuses, such as PCs, specialized printers, recording apparatuses, digital audio players, and the like. Once stored in memory, the files can be administered (e.g., edited, enhanced, reproduced, erased and the like) on an individual basis. A movie file, for example, typically consists of several frames. Administering a movie file involves opening the file and accessing the movie stream on a frame-by-frame basis.
Various standards have been established in an attempt to provide a uniform set of guidelines for arranging digital data in a file and organizing the files in a storage device. For example, the Exchangeable Image File Format (“EXIF”) standard provides rules for storing information in image files, such as exposure details, and for using JPEG compression. Another standard, the “Design Rule for Camera File” (or “DCF”) standard, specifies rules which add limitations to the EXIF standard for the sake of playback compatibility. In particular, the DCF standard defines how an image is stored as well as its filename extension. An image file or “DCF Basic File” is stored under a DCF directory, has a DCF filename and extension, and as mentioned above, a data structure in compliance with the EXIF standard. Image data in a DCF Basic file is compressed using the JPEG-compression algorithms, where the JPEG compression used is lossy. A DCF-compatible digital camera, for example, can display images recorded with other DCF-compatible digital cameras. Also, a DCF-compatible printer can be used to print images from DCF-compatible cameras of different makes. DCF-compatible software also supports importing images from DCF images, regardless of their source.
Standards also have been established in an attempt to provide a uniform set of guidelines for interfacing recording and reproducing apparatus. For example, PictBridge™ technology enables a recording apparatus to be directly connected to a printer via a Universal Serial Bus (“USB”) cable to print one or more image frames. This interface technique also converts the frame data to be compatible with the interface.
Methods have been proposed for administrating how image data is recorded on a recording medium. One proposed method is disclosed in Japan Laid Open No. JPA-2002051302 (Hiroki et al.). Hiroki et al. disclose generating administrative information such as recording mode, type of image, and the like, simultaneously with the image recording operation. When image data is transferred to a memory card, the central processing unit (“CPU”) combines the administrative information with the image data. The administration information is organized as the combination of a header and the image data, where the header information corresponds to the selected recording mode. In a continuous mode, for example, the header of the file can include information such as group number, group type, number of image files, and image file serial numbers.
Japanese Laid Open No. JPA-2000287162 (Junya) discloses a digital camera that can reproduce several still images at different frame rates. The Junya camera records onto a memory card a primary file including still pictures as well as index information to manage the respective still pictures. The primary file also includes a thumbnail file including thumbnail still pictures corresponding to the respective still pictures and index information to manage the respective thumbnail still pictures. When reproducing the data, a CPU reproduces a still picture for each frame at a “usual” speed on the basis of an index table generated on the basis of two index information sets. When high speed reproduction is instructed, the CPU reproduces thumbnail still pictures after a second frame and succeeding frames in response to an end signal from a JPEG coder/decoder (“CODEC”).
The above-described techniques require image administration information, such as how the digital image files are stored and indexed in memory, as well as information relating to the image taking parameters. In many cases, the image administration information is prepared separately for each image recording. As a result, administering a file must be performed on frame-by-frame basis and requires editing of the image administration information. Since the administration information data is grouped separately from the image data, editing such image files becomes complex.